Comparison of transient behaviors of wind turbines with DFIG considering the shaft flexible models

In order to investigate the impacts of the integration of wind farms into utilities network, it is necessary to analyze the transient performances of wind power generation systems. In this paper, an assessment of the impact that the different representations of drive-train dynamics have on the electrical transient performances of doubly fed induction generator (DFIG) wind turbines with different operationally states is investigated. In order to compare the transient performances of DFIG wind turbines during electrical transients, a DFIG model with simple one-mass lumped model and a two-mass shaft flexible model of wind turbine drive train systems are presented including the control strategies of the grid side and rotor side converters. The transient performances of DFIG wind turbines are evaluated under super- and sub-synchronous operation during different grid voltage dips. Simulation results have shown that it is needed to consider two mass shaft flexible model for the sake of exact analysis of transient behavior of DFIG wind turbines, especially when a more serious grid voltage dips occurs in power system and DFIG is at super-synchronous operation.